Clinical experience with a proximally porous-coated second-generation cementless total hip prosthesis - Minimum 5-year follow-up

This study reports the minimum 5-year follow-up of our experience with the Porous-Coated Anatomic E [PCA-E) series femoral stem and the modular acetab ular cup. A total of 115 consecutive total hip replacements using PCA-E ser ies (Howmedica, Rutherford NJ) were performed in 108 patients. Six patients whose hips were performing well clinically died before 5-year follow-up an d were excluded from the final evaluation. The remaining 109 hips (102 pati ents) were assessed at a mean follow-up of 72 months (range, 60-84 months). The hip diagnoses were osteoarthritis in 73, osteonecrosis in 31, rheumato id arthritis in 2, and hip dysplasia in 3. The mean age was 56 years (range , 24-83 years). Three hips were revised: 1 because of Late hematogenous inf ection, 1 because of aseptic loosening of the femoral component, and 1 beca use of postoperative lessening of an acetabular component. The Harris hip s cores improved from a mean of 50 points (range, 20-66 points) preoperativel y to a mean of 92 points (range, 64-100 points) at final follow-up. The sco re differed in each Charnley functional class, with a mean of 93 points (ra nge, 72-100 points) in 57 hips of class A (no other joint involvement); 90 points (range, 58-100 points) in 26 hips of class B (opposite hip involveme nt); and 85 points (range, 37-100 points) in 26 hips of class C (multiple j oint involvement or severe systemic disease). Out of 106 hips that had a fu ll radiographic evaluation performed, 103 femoral components revealed stabl e bony ingrowth, 2 revealed stable fibrous ingrowth, and 1 showed migration with progressive loosening. This patient with radiographic loosening has m inimal symptoms and has not required or been offered further surgery (Harri s hip score of 86 points). The low aseptic loosening rate (2%) at minimum 5 -year follow-up compares favorably with any cemented or cementless series. The osteolysis that was seen was focal and localized. The short follow-up d oes not allow determination of progression. There were no cases of distal o steolysis. We attribute the improved results from reported first-generation experience to multiple factors, including increased number of sizes (9 vs 6), increased proportional metaphyseal size, improved polyethylene manufact ure iran extruded vs machined), improved acetabular locking mechanism and c hange to 26-mm from 32-mm femoral heads.